xref: /freebsd/lib/msun/src/s_fmaxl.c (revision 397e83df75e0fcd0d3fcb95ae4d794cb7600fc89)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2004 David Schultz <das@FreeBSD.ORG>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <math.h>
30 
31 #include "fpmath.h"
32 
33 long double
34 fmaxl(long double x, long double y)
35 {
36 	union IEEEl2bits u[2];
37 
38 	u[0].e = x;
39 	mask_nbit_l(u[0]);
40 	u[1].e = y;
41 	mask_nbit_l(u[1]);
42 
43 	/* Check for NaNs to avoid raising spurious exceptions. */
44 	if (u[0].bits.exp == 32767 && (u[0].bits.manh | u[0].bits.manl) != 0)
45 		return (y);
46 	if (u[1].bits.exp == 32767 && (u[1].bits.manh | u[1].bits.manl) != 0)
47 		return (x);
48 
49 	/* Handle comparisons of signed zeroes. */
50 	if (u[0].bits.sign != u[1].bits.sign)
51 		return (u[0].bits.sign ? y : x);
52 
53 	return (x > y ? x : y);
54 }
55